In the second year after the Israelites’ departure from the land of Egypt, on the first day of the second month, the Lord said to Moses at the tent of meeting in the wilderness of Sinai:
But you shall celebrate it in the second month, on the fourteenth day of that month during the evening twilight, eating it with unleavened bread and bitter herbs,
and they did celebrate the Passover on the fourteenth day of the first month during the evening twilight in the wilderness of Sinai. Just as the Lord had commanded Moses, so the Israelites did.